Focussz Fosc21

The Focussz Fosc21 is a USB-based, 2-channel oscilloscope with an analog bandwidth of 3kHz and a sampling rate of 8kHz (1 channel) / 4kHz (2 channels). The manufacturer improperly calls this device an oscilloscope: It can only measure voltages from 0-5V, and thus cannot measure negative voltages.